In the Inspector window, select Settings for iOS (the iPhone icon) > Other Settings.

In the Configuration section of the Inspector window, locate Target SDK and select:

Device SDK, if you want to run your application on a physical device.

Simulator SDK, if you want to run your application on an iOS Simulator.

(Optional, if you want to use Unity Remote) Go to Edit > Project Settings > Editor to bring up the Editor Settings window and navigate to the Unity Remote section. Set the Device setting to Any iOS Device.

(Optional) Set up Unity Remote

Unity Remote is Unity’s solution for faster mobile development iteration times. Check out Unity’s documentation for more information and setup instructions.